An advanced diamond-wing configuration was tested at low speeds in the National Transonic Facility (NTF) in air at chord Reynolds numbers from 4.4 million (typical wind-tunnel conditions) to 24 million (nominal flight value). Extensive variations on high-lift rigging were explored as part of a broad multinational program. The analysis for this study is focused on the cruise and landing settings of the wing high-lift systems. Three flow domains were identified from the data and provide a context for the ensuing data analysis. Reynolds number effects were examined in incremental form based upon attached-flow theory. A similar approach showed very little effect of low-speed compressibility.